scholarly journals Performance analysis of power generation by wood and woody biomass gasification in a downdraft gasifier

Author(s):  
Sahar Safarian ◽  
Runar Unnthorsson ◽  
Christiaan Richter

An equilibrium simulation model was developed by applying Aspen Plus to evaluate the performance of 28 wood and woody biomass (W&WB) gasification in a downdraft gasifier integrated with power production unit. The developed simulation model does not focus the gasification process as a closed box, it considers important processes in gasification like drying, pyrolysis, combustion, gasification and integrated with power production plant (combustion chamber plus gas turbine). The results for the 28 W&WB alternatives show that the net power produced from 1-ton feedstock entering to the gasification system is between the interval [0-400 kW/ton] and among them, gasification system derived from Tamarack bark biomass significantly outranks all other systems by producing 363 kW/ton, owing to the favorable results obtained in the performance analysis. Moreover, effect of various operating parameters such as gasification temperature and air to fuel ratio (AFR) on the system performance was carried out. Finally, the developed model is applied as an effective tool to assess the impact of so many biomasses and operating parameters on output power.

Fermentation ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 139
Author(s):  
Sahar Safarian ◽  
Runar Unnthorsson ◽  
Christiaan Richter

In this paper, a simulation model based on the non-stoichiometric equilibrium method via ASPEN Plus was established to analyze the gasification performance of 20 herbaceous and agricultural biomasses (H&ABs) linked with syngas fermentation and product purification units for ethanol production. The established simulation model does not consider the gasification system as a black box; it focuses the important processes in gasification such as drying, pyrolysis, gasification, and connection with bioethanol production plants. The results for the 20 H&AB options suggest that the specific mass flow rate of bioethanol from 1 kg of biomass input to the unit is in the range of 99–250 g/kg, and between them, the system fed by hazelnut shell biomass remarkably outranked other alternatives by 241 g/kg production due to the high beneficial results gained from the performance analysis. Additionally, a sensitivity analysis was performed by changing operating conditions such as gasification temperature and air-to-fuel ratio. The modeling results are given and discussed. The established model could be a useful approach to evaluate the impacts of a huge numbers of biomasses and operating parameters on bioethanol output.


2018 ◽  
Vol 8 (1) ◽  
pp. 21-30
Author(s):  
István Bodnár ◽  
Patrik Iski ◽  
Ádám Skribanek

Abstract This paper presents the thermokinetic modeling of the gasification process performed on the acacia-tree under varying operating circumstances and different humidity levels. Gasification does not produce flue gas, but due to imperfect burning, synthesis gas appears which is rich in flammable components (CO2 and H2). The chemical structure of this gas depends on the components of the fuel and the humidity level, but is also greatly affected by the technological parameters, such as pressure and temperature, as well as the air-ratio. The study shows the change of chemical composition, fuel value and the reaction efficiency as a function of varying gasification temperature and pressure. Rising temperature results in improved efficiency, while higher pressure worsens reaction efficiency. However, at higher temperature intervals, the effect of the pressure is neglectable.


2017 ◽  
Vol 19 (3) ◽  
pp. 245 ◽  
Author(s):  
A. Fedyukhin ◽  
I. Sultanguzin ◽  
A. Gyul’maliev ◽  
V. Sergeev

Thermogravimetric experiments were carried out for a few types of wood with determination of the kinetic parameters characterizing the pyrolysis process. In the present work the various kinetic models used for this purpose are suggested. Analyzing software tool for calculation of thermal conversion products and reactor balance is developed. The optimal temperature range for biomass pyrolysis is identified using this tool. The influence of steam and air flow rates on the gasification products is represented. The impact of operating parameters on the synthesis gas composition was evaluated. Comparison of the computational model and the results obtained during experimental studies on the existing gasifier were carried out. The combined cycle power plant involving the biomass gasification process has been numerically simulated in the Aspen Plus. Calculations of the optimal operating parameters of different thermal process components and of the entire combined cycle power plant system were performed.


2021 ◽  
Vol 13 (21) ◽  
pp. 11763
Author(s):  
Alejandro Lyons Cerón ◽  
Alar Konist ◽  
Heidi Lees ◽  
Oliver Järvik

Using woody biomass in thermochemical gasification can be a viable alternative for producing renewable energy. The type of biomass and the process parameters influence the producer gas composition and quality. This paper presents research on the composition of the producer gas from the gasification of three woody biomass species: spruce, alder, and pine. The experiments were conducted in a drop-tube reactor at temperatures of 750, 850, and 950 °C, using air as the gasifying agent, with equivalence ratios of 0.38 and 0.19. Gas chromatography with a thermal conductivity detector was used to determine the composition of the producer gas, while the production of total organic compounds was detected using Fourier-transform infrared spectroscopy. All three wood species exhibited very similar producer gas composition. The highest concentration of combustible gases was recorded at 950 °C, with an average of 4.1, 20.5, and 4.6 vol% for H2, CO, and CH4, respectively, and a LHV ranging from 4.3–5.1 MJ/m3. The results were in accordance with other gasification studies of woody species. Higher temperatures enhanced the composition of the producer gas by promoting endothermic and exothermic gasification reactions, increasing gas production while lowering solid and tar yields. The highest concentrations of combustible gases were observed with an equivalence ratio of 0.38. Continuous TOC measurement allowed understanding the evolution of the gasification process and the relation between a higher production of TOC and CO as the gasification temperature raised.


Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3225 ◽  
Author(s):  
Tejasvi Sharma ◽  
Diego Yepes Maya ◽  
Francisco M. Nascimento ◽  
Yunye Shi ◽  
Albert Ratner ◽  
...  

The goal of this work is to understand the gasification process for Miscanthus briquettes in a double-stage downdraft gasifier, and the impact of different Equivalence Ratios (ER) on syngas, biochar, and tar characteristics. The optimal ER was found to be 0.35, which yielded a syngas maximum heating value of 5.5 MJ/Nm3 with a syngas composition of 20.29% CO, 18.68% H2, and 0.86% CH4. To better understand the observed behavior, an equilibrium reaction model was created and validated using the experimental data. The model showed that the heating value decreased with increasing ER, and that hydrogen production peaked at ER = 0.37, while methane (CH4) became negligible above ER = 0.42. Tar and particle content in the gas produced at a certain temperature can now be predicted. To assess the biochar characteristics, surface structure image analysis and a surface area porosity analysis were carried out. Employing images from a scanning electron microscope (SEM), the biochar cell bonds and pore structures were examined and analyzed. By using the Brunauer-Emmett-Teller (BET) analysis of the surface porosity, the surface area to be 186.06 m2/g and the micro pore volume was calculated to be 0.07 m3/g. The final aspect of the analysis involved an evaluation of tar production. Combining current and prior data showed a logarithmic relationship between the amount of tar produced and the gasifier bed temperature, where the amount of tar produced decreased with increasing bed temperature. This results in very low tar levels, which is one of the known advantages for a double-stage downdraft gasifier over a single-stage system.


2019 ◽  
Vol 11 (6) ◽  
pp. 1782 ◽  
Author(s):  
Jacek Szulej ◽  
Paweł Ogrodnik ◽  
Beata Klimek

The article presents the results of research on the use of ceramic ware waste as aggregate in concrete production. Four concrete mixtures with aluminous cement were prepared, each with a different admixture of clinoptilolite. The only used aggregate was crushed waste ceramic sanitary ware obtained from a Polish sanitary fixture production plant. As part of the studies, a compressive test of cubic samples at different curing times ranging from 7 to 90 days was performed. Prior to the preparation of the samples, a sieve analysis and an elemental analysis of the obtained aggregate were conducted. In the framework of the testing, the bimodal distribution of clinoptilolite grains was determined, as well as its chemical composition. The conducted compressive tests demonstrated high strength of concrete containing ceramic aggregate and aluminous cement with an addition of clinoptilolite. In order to determine the impact that adding zeolite exerts on the phase composition and the structure of concrete samples, an analysis of the phase composition (XRD) and scanning electron microscopy examination (SEM) were performed. Furthermore, tests of abrasion, water penetration under pressure and frost resistance were conducted, determining particular properties of the designed mixtures. The abrasion tests have confirmed that the mixtures are highly abrasion-resistant and can be used as a topcoat concrete layer. The conducted tests of selected properties have confirmed the possibility of using waste ceramic cullet and a mineral addition of clinoptilolite in concrete production.


2012 ◽  
Vol 43 (1-2) ◽  
pp. 54-63 ◽  
Author(s):  
Baohong Lu ◽  
Huanghe Gu ◽  
Ziyin Xie ◽  
Jiufu Liu ◽  
Lejun Ma ◽  
...  

Stochastic simulation is widely applied for estimating the design flood of various hydrosystems. The design flood at a reservoir site should consider the impact of upstream reservoirs, along with any development of hydropower. This paper investigates and applies a stochastic simulation approach for determining the design flood of a complex cascade of reservoirs in the Longtan watershed, southern China. The magnitude of the design flood when the impact of the upstream reservoirs is considered is less than that without considering them. In particular, the stochastic simulation model takes into account both systematic and historical flood records. As the reliability of the frequency analysis increases with more representative samples, it is desirable to incorporate historical flood records, if available, into the stochastic simulation model. This study shows that the design values from the stochastic simulation method with historical flood records are higher than those without historical flood records. The paper demonstrates the advantages of adopting a stochastic flow simulation approach to address design-flood-related issues for a complex cascade reservoir system.


Electronics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 632
Author(s):  
Xiaozheng Wang ◽  
Minglun Zhang ◽  
Hongyu Zhou ◽  
Xiaomin Ren

The performance of the underwater optical wireless communication (UOWC) system is highly affected by seawater´s inherent optical properties and the solar radiation from sunlight, especially for a shallow environment. The multipath effect and degradations in signal-to-noise ratio (SNR) due to absorption, scattering, and ambient noises can significantly limit the viable communication range, which poses key challenges to its large-scale commercial applications. To this end, this paper proposes a unified model for underwater channel characterization and system performance analysis in the presence of solar noises utilizing a photon tracing algorithm. Besides, we developed a generic simulation platform with configurable parameters and self-defined scenarios via MATLAB. Based on this platform, a comprehensive investigation of underwater channel impairments was conducted including temporal and spatial dispersion, illumination distribution pattern, and statistical attenuation with various oceanic types. The impact of ambient noise at different operation depths on the bit error rate (BER) performance of the shallow UOWC system was evaluated under typical specifications. Simulation results revealed that the multipath dispersion is tied closely to the multiple scattering phenomenon. The delay spread and ambient noise effect can be mitigated by considering a narrow field of view (FOV) and it also enables the system to exhibit optimal performance on combining with a wide aperture.


Electronics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 644
Author(s):  
Michal Frivaldsky ◽  
Jan Morgos ◽  
Michal Prazenica ◽  
Kristian Takacs

In this paper, we describe a procedure for designing an accurate simulation model using a price-wised linear approach referred to as the power semiconductor converters of a DC microgrid concept. Initially, the selection of topologies of individual power stage blocs are identified. Due to the requirements for verifying the accuracy of the simulation model, physical samples of power converters are realized with a power ratio of 1:10. The focus was on optimization of operational parameters such as real-time behavior (variable waveforms within a time domain), efficiency, and the voltage/current ripples. The approach was compared to real-time operation and efficiency performance was evaluated showing the accuracy and suitability of the presented approach. The results show the potential for developing complex smart grid simulation models, with a high level of accuracy, and thus the possibility to investigate various operational scenarios and the impact of power converter characteristics on the performance of a smart gird. Two possible operational scenarios of the proposed smart grid concept are evaluated and demonstrate that an accurate hardware-in-the-loop (HIL) system can be designed.


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